Laundry that has been cleaned with a commercial laundry detergent and dried thereafter usually has a stiff appearance and feels hard to the touch. Fabric softeners are commonly used to provide laundry with a more comfortable soft touch. Such fabric softeners are applied after the wash, usually in the form of a rinse cycle fabric softener that is added to a rinse after the wash cycle. Such separate use of a laundry detergent and fabric softener is inconvenient and therefore numerous attempts have been made to provide a laundry detergent that has a fabric softening action.
The fabric softening actives of the quaternary ammonium salt type commonly used in fabric softeners cannot be used in laundry detergent formulations containing an anionic surfactant, because they form insoluble salts with the anionic surfactant. A range of alternative fabric softening actives have been suggested for incorporation into laundry detergents, but there is still a need for fabric softening actives and that can be formulated with a large a range of anionic surfactants and provide laundry detergents with improved softening action.
U.S. Pat. No. 5,622,925 discloses liquid laundry detergents with softening properties comprising an anionic surfactant and a quaternary ammonium fabric softening agent of a specified structure. Compounds of this type have found commercial use in laundry detergents with fabric softening action.
WO 90/03423 discloses the use of alkoxypropylamines with a C8-22 alkoxy group as detergency enhancing additives for laundry detergents comprising anionic or nonionic surfactants. The document contains no disclosure of a fabric softening action of the described laundry detergents and does not suggest to use the disclosed laundry detergents for softening fabrics without the use of an additional fabric softener.
U.S. Pat. No. 5,981,466 and WO 97/12021 disclose the use of specific primary and/or tertiary amines, encompassing alkoxypropylamines with a C4-18 alkoxy group, as suds suppressing additives for liquid laundry detergents comprising an alkyl alkoxy sulfate and/or alkyl sulfate surfactant. The documents contain no disclosure of a fabric softening action of the described laundry detergents and do not suggest to use the disclosed laundry detergents for softening fabrics without the use of an additional fabric softener.
WO 96/12004 discloses detergents, comprising a lipolytic enzyme and specific primary and/or tertiary amines, encompassing alkoxypropylamines with a C6-12 alkoxy group, having enhanced detergency for grease and oil stains. The detergents may also contain anionic or nonionic surfactants. The document contains no disclosure of a fabric softening action of the described laundry detergents and does not suggest to use the disclosed laundry detergents for softening fabrics without the use of an additional fabric softener.
U.S. Pat. No. 5,871,590 discloses vehicle cleaning compositions containing fatty alkyl ether amines and a nonionic surfactant. The fatty alkyl ether amines encompass alkoxypropylamines and alkoxypropylaminopropylamines with C6-28 alkoxy groups. The disclosure is not related to laundry detergents.
GB 1 601 359 discloses rinse cycle fabric softeners comprising a combination of a cationic surfactant and specific nonionic fabric lubricants. The disclosed cationic surfactants encompass salts of alkoxypropylamines and alkoxypropylaminopropylamines with C8-22 alkoxy groups. The cationic surfactant acts as a carrier material to provide deposition of the nonionic onto fabrics. The document does not disclose that the cationic surfactants provide a softening action on their own.
U.S. Pat. No. 6,737,050 discloses hair cleansing compositions comprising anionic and/or nonionic surfactants and quaternary ammonium salts having one C6-24 alkoxypropyl group and three alkyl or hydroxyalkyl groups as substituents. The disclosed hair cleansing compositions impart good flexibility and smoothness to human hair. The document does not disclose the use of such compositions for treating fabrics.
U.S. Pat. No. 6,191,099 discloses a method for cleaning hydrocarbon-containing soils from surfaces using a detergent comprising a quaternary ammonium compound and a nonionic surfactant. The quaternary ammonium compounds encompass compounds having one C6-22 alkoxypropyl group, as well as three methyl groups or a methyl group and two hydroxyalkyl groups bonded to the same nitrogen atom. The document contains no disclosure of a fabric softening action of the described detergent and does not suggest to use the disclosed detergent for softening fabrics.
Applicants have now found that alkoxypropylamine compounds of structures (I) and (II) and the salts of compounds of structure (I) are surprisingly efficient in softening fabrics when used in a laundry detergent comprising an anionic and/or nonionic surfactant.R1—O—(CH2)3—NHR2  (I)R1—O—(CH2)3—NR32(CH3)+X−  (II)    R1 is a C8-20 alkyl group,    R2 is hydrogen or (CH2)3NH2,    R3 is CH3 or CH2CH2OH and    X− is an anion
The alkoxypropylamine compounds of the invention have not been described as fabric softening actives up to now and therefore their fabric softening properties were not predictable.